A husband and wife in their mid-thirties, Steve and Diane, are on a hike up a mountainside as part of an attempt to reinvigorate their marriage when a mist descends suddenly and they’re forced to backtrack. On the way down, they decide to follow a seemingly easier side trail, but after a while they realize they’re lost. After a short dispute they decide to return to the main trail, but suddenly hear a dog barking in the distance and a person shouting “hello”. They walk towards the voice, hoping for rescue, and end up on the gravelly rock surface of a moraine. A lamb stumbles towards them, bleating, and as they watch a figure rushes under the rocks towards it and then brutally kills it. The figure then repeats, “hello,” in the same voice they heard before. Realizing they’re in danger of being hunted, Steve and Diane carefully make their way back up towards the solid ground of the trail until the monster catches on to them and races to block their path. They turn back and make it onto a boulder just before it catches them. After a while on the boulder, the couple decides that they have to make a run for a second boulder that appears to be closer to solid ground, where the creature can’t follow. They throw stones in the opposite direction of their path to mislead the monster and then run, but it catches Diane, drags her halfway under, and destroys her legs. She tells Steve to run and get help if he can, and he agrees after they tell each other they love one another. He finds solid ground and escapes the creature, but still doesn’t have a path to follow. He wanders through the mist, hoping to find a way down, as the knowledge that Diane may still be alive is enough to keep him going even as hypothermia sets in.